
where \(\Delta h_\mathbf {m} \triangleq h(\zeta _{\mathbf {m}}^-)-h(\zeta _{\mathbf {m}}^+)\) . Then, applying the Clarke Mean Value Theorem [1]} to \(\Delta h_\mathbf {m}\) , there exists \(\xi \in [{\underline{J}^{h}_C},{\overline{J}^{h}_C}] \subset \mathbf {M}_i\)  such that
\(\Delta h_{\mathbf {m}}= \langle \xi ,(\zeta _{\mathbf {m}}^+ - \zeta _{\mathbf {m}}^-)\rangle .\) 
